In the past, as a system for producing gas used in a semiconductor manufacturing process such as a deposition process, as disclosed in Patent Literature 1, a vaporization system adapted to vaporize a liquid material has been used.
As this sort of vaporization system, there is one configured to provide a pressure sensor in a flow path for vaporized gas produced by a vaporizer and monitor pressure in the vaporizer. In doing so, when the pressure in the vaporizer falls as the amount of a liquid material in the vaporizer decreases and falls below a threshold value, by supplying the liquid material to the vaporizer, the liquid material in the vaporizer is prevented from running out, or when the pressure in the vaporizer rises as the liquid material is supplied to the vaporizer and exceeds the threshold value, by stopping supplying the liquid material, the liquid material is prevented from overflowing from the vaporizer.
However, when providing the pressure sensor in the flow path for the vaporized gas, the pressure sensor has to be one resistant to high temperature, and such a pressure sensor is expensive and/or large in size, thus preventing reductions in cost and size.
Further, when calibrating the pressure sensor, such as correcting the zero point of the pressure sensor, it is necessary to evacuate the vaporizer, causing the problem of poor maintainability as well.